PHOTODISSOCIATION OF MAGNESIUM-ION MOLECULE COMPLEXES IN A REFLECTRON TIME-OF-FLIGHT MASS-SPECTROMETER

Ion/molecule cluster complexes containing magnesium (e.g., Mg+-(CO2)x, Mg+-(H2O)x) are generated in a pulsed nozzle cluster source. Specific ions are size selected from the source distribution with a reflectron time-of-flight mass spectrometer for studies of their photodissociation dynamics. Photoexcitation of these complexes near the Mg+ (2S --> 2P) resonance line causes a variety of novel photochemistry, ranging from simple ligand ejection, to metal insertion, to metal-ligand charge exchange. These reactions arc first observed in the single molecule complexes, and they persist in larger aggregates with more extensive solvation. Excitation spectra probe the energy dependence of the photochemistry and they provide information on the structures of the ion/molecule complexes.